Does breastfeeding reduce the risk of child overweight in North Carolina?

No. 164 October 2010
Does Breastfeeding Reduce the Risk of
Child Overweight in North Carolina?
by
Harry Herrick, M.S.P.H., M.S.W., M.Ed.
Donna R. Miles, Ph.D.
Catherine Sullivan, M.P.H., R.D., L.D.N., I.B.C.L.C., R.L.C.
Abstract
Objectives: Numerous studies have found an association between breastfeeding and the risk of child overweight. Our
objective is to examine the relationship between breastfeeding initiation and duration with child overweight among
children and adolescents in North Carolina, while controlling for maternal characteristics.
Methods: From 2007–2009, 3,424 biological mothers completed both the North Carolina Behavior Risk Factor
Surveillance System (BRFSS) and the Child Health Assessment and Monitoring Program (CHAMP) surveys. These
population-based data were used to analyze child overweight (ages 2 to 17 years) among children who were never
breastfed or weaned at an early age (breastfed less than three months), as compared to children who were breastfed for at
least three months.
Results: Multivariate analysis found that breastfeeding duration is significantly associated with child overweight/obesity,
even after controlling for maternal characteristics including race, education, smoking status, and weight status. Children
who were never breastfed were significantly more likely to be overweight/obese (aOR=1.39 [95% CI 1.08, 1.80]), as well
as children who were breastfed for less than three months (aOR=1.33 [95% CI 1.03, 1.71]), compared to children who
were breastfed for three or more months.
Conclusion: Various initiatives aimed at childhood obesity include recommendations promoting breastfeeding. Providing
education and information on breastfeeding, supporting programs to encourage breastfeeding, as well as advancing state
breastfeeding legislation may help reduce the rate of child overweight and obesity.
Harry Herrick and Donna R. Miles are with the State Center for Health Statistics, North Carolina Department of Health and Human Services.
Catherine Sullivan is the State Breastfeeding Coordinator, Nutrition Services Branch, North Carolina Department of Health and Human Services.
SCHS Study No. 164 ♦ October 2010 2 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
Introduction
The benefits of breastfeeding in reducing the risk of childhood overweight have been well-documented. Two meta-analyses* conducted by Arenz et al.1 and Owen et al.2 report that breastfeeding has an inverse association with childhood overweight. Arenz and colleagues examined nine studies, consisting of more than 69,000 participants, and concluded that the likelihood of childhood obesity was 22 percent lower for children who were breastfed as infants compared to those never-breastfed (aOR 0.78 [95% CI 0.71–0.85]). Four of the studies in the Arenz et al. review also reported a decreasing prevalence of overweight with increasing duration of breastfeeding, suggesting an inverse dose-response relationship between breastfeeding duration and obesity. Owen and colleagues reviewed 28 studies, consisting of 298,900 subjects, and also found lower adjusted odds of obesity among breastfed children than among formula-fed children. The relationship between breastfeeding and obesity persisted for older children and adolescents indicating that the benefits of breastfeeding were not limited to early childhood.
Low rates of breastfeeding initiation have long been known to be associated with certain maternal characteristics. Results from the Centers for Disease Control and Prevention (CDC) National Immunization Survey3,4 found that, among infants born in 2006, the overall national rate of breastfeeding initiation was 74 percent. However, for this same birth cohort, breastfeeding initiation varied by maternal education and race/ethnicity. Among mothers with a high school education, breastfeeding initiation was 65 percent, compared to 86 percent among mothers with a college degree. Furthermore, the breastfeeding initiation rate among non-Hispanic African-American mothers was the lowest of any race or ethnic group at 56 percent. Also, maternal smoking and maternal obesity have been associated with decreased rates of breastfeeding initiation and duration.5,6
In addition to research demonstrating the benefits of breastfeeding, strategies to encourage breastfeeding have recently gained national attention. On May 11, 2010, First Lady Michelle Obama unveiled the White House Child Obesity Task Force action plan: Solving the Problem of Childhood Obesity Within a Generation.7 In the unveiling of this plan, Mrs. Obama said: “For the first time, the nation will have goals, benchmarks, and measureable outcomes that will help us tackle the childhood obesity epidemic one child, one family, and one community at a time.”8 In this plan, there are several recommendations specific to the promotion of breastfeeding which include eliciting hospitals and health care providers to empower new mothers to breastfeed, improving breastfeeding support among childcare settings, and eliciting local health departments to develop support programs to encourage and sustain breastfeeding for new mothers.
The purpose of the current study is to examine the association between breastfeeding and child overweight status in North Carolina. Using results from the North Carolina Child Health Assessment and Monitoring Program (CHAMP) Survey, we examined whether the likelihood of being overweight was significantly greater among children who were never breastfed or weaned at an early age (breastfed less than three months), as compared to children who were breastfed for at least three months.
Methods
Data
We combined survey data from the 2007, 2008, and 2009 North Carolina Behavioral Risk Factor Surveillance System (BRFSS) and CHAMP surveys to yield a sufficiently large sample for conducting a multivariate analysis of breastfeeding and its association with child and adolescent overweight. The BRFSS is an annual state-wide telephone survey that uses a random-digit-dial computer-assisted telephone interview to assess health characteristics of non-institutionalized adults age 18 years and older. During the BRFSS interview, respondents living in households with children (0 to 17 years) are asked to participate in CHAMP. One child is randomly selected from the household and the adult identified as most knowledgeable about the health of the selected child is called one to two weeks later to complete the CHAMP survey.9
From 2007–2009, 43,889 adults participated in the NC BRFSS. A total of 12,767 (29%) reported a child under age 18 living in the household, of which 8,072 (63%) participated in CHAMP. The current study was limited to surveys where the CHAMP child’s biological mother completed both the BRFSS and CHAMP surveys, and provided information on the child’s height and weight (N=3,424).
* Meta-analyses are studies of previously published studies on a given topic which meet certain research criteria. In a meta-analysis, the study itself is the unit of analysis. For the two studies mentioned above, the authors “pooled” the reported results from each study to yield a summary risk estimate, or pooled odds ratio.State Center for Health Statistics 3 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
Child Weight Status
Child weight status was estimated from maternal report of child’s height and weight (ages 2 to 17 years) from which Body Mass Index (BMI) percentiles for age and sex were calculated. BMI-for-Age percentiles are endorsed as the appropriate assessment of weight status in children and are determined via CDC charting of BMI,10 which is calculated in the same manner for children as it is for adults: weight (in kilograms) divided by height (in meters) squared. In this study, we defined the prevalence of child overweight as having a BMI equal to or exceeding the age-sex-specific 85th percentile, which also includes children defined as obese (greater than 95th percentile). Child overweight was treated as a dichotomous (yes/no) variable. Children with implausible values of height, weight or BMI were excluded from the study, using World Health Organization exclusion criteria.11
Breastfeeding
Breastfeeding initiation and duration were measured in the 2007–2009 CHAMP surveys. For this study, breastfeeding duration was categorized as: (1) never breastfed, (2) breastfed for less than three months
(1 to 90 days), and (3) breastfed for three or more
months (91+ days).
Maternal Characteristics
Demographic and behavioral characteristics of the mother, including education, race, smoking (current smoker vs. non-smoker), and weight status were obtained from the 2007–2009 BRFSS surveys. Three categories of race were analyzed: white, African American, and other. Hispanic mothers accounted for 64 percent of “other race.” Due to small numbers, Hispanics were not treated as separate group in the logistic regression model.
Maternal weight status was based on self-reported height and weight. Categories for maternal weight status based on BMI were defined as: BMI less than 18.5 classified as underweight; BMI 18.5 to 24.9 classified as normal weight; BMI 25.0 to 29.9 classified as overweight; and BMI greater than 29.9 classified as obese.12 For this study, underweight and normal weight mothers were collapsed into a single group, while overweight and obese mothers were treated as separate groups.
Statistical Analysis
CHAMP data are weighted to represent the total child population (0 to 17 years) of North Carolina. SUDAAN 10.0 software survey procedures were used to account for the complex survey design. All descriptive and multivariate analyses incorporated the sample weights and variance estimators derived from the survey design. Multiple logistic regression was used to compute the adjusted odds ratios for overweight children (the dependent variable), accounting for the effects of breastfeeding duration, maternal race, education, smoking, and weight status (explanatory variables). In this model of child overweight, we controlled for maternal characteristics that are associated with breastfeeding.
Results
Sample Characteristics
Demographic and behavioral characteristics of survey respondents are presented in Table 1. Seventy-one percent
Table 1
Sample Characteristics: 2007–2009 NC BRFSS and CHAMP Surveys (N = 3,424)
N
Weighted Percent
Maternal race
African American
458
19.2
Other race
296
10.2
White
2,659
70.6
Maternal education
Less than or equal to H.S.
939
27.9
Some College/Tech school
1,065
30.7
College graduate
1,419
41.4
Maternal smoking status
Current smoker
666
17.8
Non-smoker
2,752
82.2
Maternal weight status
Obese
961
30.6
Overweight
933
28.7
Normal/underweight
1,363
40.7
Child weight status
Underweight
209
6.5
Normal weight
2,049
59.0
Overweight
555
16.8
Obese
611
17.7
Breastfeeding duration
No days
1,092
31.7
Less than 3 months
893
25.3
3 months or more
1,328
43.0SCHS Study No. 164 ♦ October 2010 4 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
of mothers were white, 19 percent African American, and 10 percent other race. Forty-one percent were college graduates, 31 percent had attended some college or technical school, and 28 percent had a high school education or less. Eighteen percent of mothers were current smokers. Based on BMI categories, 41 percent of mothers were underweight/normal weight, while 28 percent were overweight and 31 percent were obese. Based on child BMI-Age percentile categories, 6 percent of children were underweight, 59 percent were normal weight, 17 percent were overweight, and 18 percent were obese; thus 35 percent of children were categorized as either overweight or obese. Overall, 32 percent of children were never breastfed, 25 percent were breastfed for less than three months, and 43 percent were breastfed for three or more months.
Prevalence and Adjusted Odds of Child Overweight
The unadjusted prevalence and adjusted odds ratios of child overweight for each of the five maternal characteristics included in the logistic regression model are presented in Table 2. Multivariate analysis found that breastfeeding duration is significantly associated with child overweight/obesity, even after controlling for maternal race, education, smoking status, and weight status. Children who were never breastfed were significantly more likely to be overweight/obese (aOR=1.39 [95% CI 1.08, 1.80]), as were children who were breastfed for less than three months (aOR=1.33 [95% CI 1.03, 1.71]), compared with children who were breastfed for three or more months.
In addition, the prevalence of child overweight was found to vary significantly by maternal race, education, smoking status, and weight status. Although the prevalence of child overweight was significantly lower among whites, multivariate analysis found that race was not a significant predictor of child overweight when controlling for other covariates. However, it was found that the adjusted odds of child overweight among mothers with the least amount of education was significantly higher compared to children of mothers with a college degree (aOR=1.43 [95% CI 1.09, 1.87]). Both the unadjusted prevalence and adjusted odds of child overweight was significantly greater among mothers who were current smokers, compared to non-smoking mothers. The strongest predictor of child overweight was maternal weight status. Obese mothers were more than two times as likely to have an overweight/obese child compared to normal weight mothers. Similarly, children of overweight mothers were also much more likely to be overweight/obese (aOR=1.33 [95% CI 1.03, 1.71]).
Table 2
Prevalence of Child Overweight/Obesity by Maternal Characteristics, 2007–2009 NC CHAMP (N = 3,383).
Maternal Characteristics
Weighted Percent of Child Overweight/Obese % (95% CI)
aOR1 (95% CI)
Breastfeeding Duration
Never breastfed
42.8 (38.9–46.7)
1.39** (1.08–1.80)
Breastfed < 3 Months
35.8 (31.8–40.0)
1.33* (1.03–1.71)
Breastfed 3 or More Months
27.7 (24.7–30.9)
1.0 (referent)
Race
African American
43.8 (38.4–49.4)
1.28 (0.97–1.69)
Other Race
40.5 (33.5–47.8)
1.40 (0.97–2.03)
White
31.1 (28.8–33.4)
1.0 (referent)
Education
Less than or Equal to H.S.
44.8 (40.6–49.1)
1.43** (1.09–1.87)
Some College/Tech School
35.6 (31.9–39.5)
1.08 (0.85–1.38)
College Graduate
26.6 (23.7–29.6)
1.0 (referent)
Smoking Status
Current Smoker
44.1 (39.3–49.1)
1.41** (1.10–1.82)
Non-smoker
32.4 (30.1–34.7)
1.0 (referent)
Maternal Weight Status
Obese
49.3 (45.2–54.8)
2.49** (1.95–3.17)
Overweight
33.8 (29.9–37.8)
1.39** (1.08–1.79)
Underweight/Normal Weight
23.9 (21.1–26.9)
1.0 (referent)
* p < .05;
** p < .01
1 aOR = Adjusted Odds Ratio; adjusted for breastfeeding duration, maternal race, education, smoking status, and weight status.State Center for Health Statistics 5 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
Discussion
Key Findings
The results of this study support the extensive body of research that has demonstrated the protective effect of breastfeeding on childhood obesity.1,2 Most notably, we found that, in comparison to children who were breastfed for three or more months, the likelihood of child overweight increased by 39 percent for children who were never breastfed, and by 33 percent for children breastfed for less than three months. This relationship was statistically significant when controlling for factors associated with low rates of breastfeeding initiation, specifically maternal race, education, smoking status, and weight status.
Among the model explanatory factors, the strongest relationship was found between maternal weight status and child weight status. Children of obese mothers were more than twice as likely to be classified as overweight or obese, as compared to children of normal weight mothers. Indeed, much of the research on maternal obesity has found that mothers who are overweight or obese entering pregnancy are likely to have infants with higher birth weight, and, in turn, these infants are also at increased risk for obesity later in life. Longitudinal birth cohort studies have shown that maternal pre-pregnancy obesity was a significant predictor of overweight among older children and adolescents.13,14 Findings from the current study of children ages 2 to 17 underscores the influence of maternal weight status on child weight status from early childhood through late adolescence. Nevertheless, breastfeeding duration remained an independent predictor of child overweight, even when controlling for the strong relationship between maternal and child weight status.
Biological Mechanisms of Breastfeeding
Several theories have been proposed to explain why breastfeeding protects against obesity.15 One theory suggests that breastfed babies work for their food by feeding at the breast; consequently, their satiety center is intact and active. Infants are thus able to self regulate their intake of breast milk by sensing when they are hungry and when they are full, rather than relying on external cues (e.g., bottle feeding).16 Other theories focus on the biochemical role of two hormones, insulin and leptin. Excessive amounts of insulin may lead to increased deposition of fat tissue, while leptin is thought to promote satiation. Breast milk has lower concentrations of insulin than formula, and formula fed infants have been shown to have higher plasma insulin concentration, likely due to higher protein intake.17 Conversely, leptin levels in breastfed babies have been found to be higher than in their formula fed counterparts.18 Lower levels of insulin and higher levels of leptin in breast milk could influence the set points of appetite or metabolism, potentially leading to longer term effects in reducing risk of child overweight.19 Further research in these emerging areas of interest is warranted.
Barriers to Breastfeeding
A mother’s decision to breastfeed can be met with barriers that affect both the desire to breastfeed and the sustainability of breastfeeding. Results from the 2008 North Carolina Pregnancy Risk Assessment Monitoring Program (PRAMS)20 found that, among mothers who never breastfed, the most common reasons for not breastfeeding were that the mother did not like breastfeeding (44%), the mother had other children to take care of (24%), or the mother had to return to school or work (23%). Other study results have shown that breastfeeding may be inhibited by underestimating the health benefits of breastfeeding,21,22 by lack of support from the baby’s father,23 and by the mother’s perceived lack of social support, or support from peers.24,25
The reasons for short-duration breastfeeding point to additional challenges for the mother. Lactation issues (baby had trouble sucking) and nutrition issues (breast milk alone did not satisfy baby) are most often cited as the primary reasons for early weaning (less than three months).26 Mother’s perception of milk insufficiency and low sense of breastfeeding self-efficacy can lead to short duration breastfeeding.27 Early weaning is also associated with birth characteristics, including prematurity, admission to a neonatal ward, and Caesarean birth.28 Women who are overweight or obese before pregnancy are also more likely to breastfeed their infants for shorter duration.29 Obesity and the hormones associated with obesity may also play a role in lactation failure.30,31 For many mothers, however, the principal reason for discontinuing breastfeeding is associated with the need to return to work.32
Strategies to Promote Breastfeeding
The Baby-Friendly Hospital Initiative (BFHI) is a well-recognized strategy that seeks to protect and promote breastfeeding worldwide. Launched in 1991, the initiative is an effort by the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO) to ensure that all maternity facilities become centers of breastfeeding support. Through implementing all UNICEF/WHO policies, known as the Ten Steps, hospitals can become certified as “baby-friendly.”33 As of July 2, SCHS Study No. 164 ♦ October 2010 6 State Center for Health Statistics
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2010, only 94 hospitals in the U.S. were certified as baby-friendly. Two of these hospitals are in North Carolina: the Mission Memorial Hospital in Asheville, and the Women’s Birth and Wellness Center in Chapel Hill.34
A number of studies both in the U.S. and in other countries have shown a positive impact of the BFHI on breastfeeding initiation and duration. An institutional survey of Oregon’s maternity hospitals (N=57) found that hospitals that had higher compliance with the BFHI Ten Steps were more likely to have higher rates of breastfeeding for their maternity patients at two days and at two weeks postpartum, compared to hospitals with lower compliance. Furthermore, when each of the Ten Steps was analyzed individually, having a written hospital policy in place was found to be the most important step associated with higher breastfeeding rates.35 A study of maternity hospitals (N=145) in Switzerland found that the proportion of exclusively breastfed infants (birth to 5 months) was 42 percent for infants born in baby-friendly hospitals, compared to 34 percent for infants born elsewhere.36 Findings from these types of studies suggest that hospitals with comprehensive breastfeeding policies are increasing the number of new mothers who initiate and sustain breastfeeding.
In 2007, the CDC Maternity Practices in Infant Nutrition and Care (mPINC) national survey assessed perinatal care in maternity hospitals and birth centers in the U.S. that provide maternity care services.37 In North Carolina, 84 percent of the 85 eligible hospitals and birth centers participated in the mPINC survey. The results of the survey revealed that in North Carolina only 9 percent of facilities met the American Academy of Pediatrics Perinatal Care Guidelines against routine supplementation of formula for newborns, only 10 percent had comprehensive breastfeeding policies in place, and only 16 percent do not distribute formula company discharge packs. The mPINC state report for North Carolina outlines recommendations to improve breastfeeding practices and policies specific to the state.38
State legislation, such as protecting a women’s right to breastfeed in public, has also been shown to be an effective strategy for promoting breastfeeding. A recent study conducted by Kogan and colleagues39 found that breastfeeding initiation rates were highest in states (predominantly in the west and northwest) that had enacted multiple pieces of legislation supportive of breastfeeding and lowest among states (predominantly southern) with minimal legislation. Washington state had the highest breastfeeding initiation rate (88%), and North Carolina ranked 31st with an initiation rate of 63.5 percent. Currently, North Carolina has a single piece of legislation stating that a woman is allowed to breastfeed in any public or private location, and that she is not in violation of indecent exposure laws. In California, with the third highest rate of breastfeeding initiation (86.5%), several pieces of legislation have been enacted, including a law that requires the Department of Public Health to develop a training course about hospital policies and recommendations that promote exclusive breastfeeding and specify staff for whom this model training is appropriate.40
Another key strategy for promoting breastfeeding involves educating employers on the health benefits of breastfeeding, and encouraging workplace policies and adaptations, such as private rooms for lactation, that would allow for new mothers to continue feeding their infant breast milk at work. Such policies have now garnered support in the new national health care bill. As part of the Patient Protection and Affordable Care Act signed by President Obama in March 2010, employers are now required to provide reasonable break time for one year for an employee who is subject to the Fair Labor Standards Act (paid hourly), to express breast milk for her nursing child, and provide a private room for this purpose.41 In North Carolina, the Office of State Personnel recently passed a lactation policy that provides space and break time for employees governed by the State Personnel Act,42 protecting salaried employees as well as hourly employees. Additional regulations went into effect on July 1, 2010, stating that all licensed child care facilities and family day care homes must provide accommodations for breastfeeding mothers, including seating and an electrical outlet in a private place other than a bathroom.43 Recently, the North Carolina Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) awarded 57 local agency Breastfeeding Promotion and Support mini-grants in the amount of $417,840 with roughly $106,000 being spent on worksite lactation efforts and $16,000 on training and lending libraries for child care facilities.
Peer support from the community with previous experience in breastfeeding their own children is also known to be effective in promoting breastfeeding. Peer supporters have been shown to be particularly helpful in working with low income populations, such as women in the WIC Program, which have traditionally low rates of breastfeeding initiation. A cross-sectional study of WIC mothers in Maryland (N=18,789) found that peer counseling was positively associated with breastfeeding State Center for Health Statistics 7 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
initiation.44 It has also been found that peer supporters may provide additional benefits to new mothers, such as increased self-esteem, greater confidence, parenting skills, and improved family diet.45 In addition, the use of community peer support programs is one of the recommendations for improving breastfeeding, as outlined in the White House Task Force Report on Solving the Problem of Childhood Obesity Within a Generation.7 The North Carolina WIC Program recently increased their peer counselor programs from 23 to 66 statewide, such that peer counselor programs are now available in all six perinatal regions of the state.
Creating a breastfeeding-friendly health care system, promoting legislation and policies that support breastfeeding, encouraging breastfeeding-friendly workplaces, and developing breastfeeding-friendly communities (e.g., local-based support groups) are some of the key recommendations outlined in North Carolina’s state plan for breastfeeding, entitled “Promoting, Protecting and Supporting Breastfeeding: A North Carolina Blueprint for Action, 2006.”46 Additional recommendations include advocating for insurance coverage for breastfeeding care, involving media to promote breastfeeding public acceptance, and encouraging research and evaluation on breastfeeding outcomes. The action steps defined in the report are also nuanced to the needs of North Carolina, such as the North Carolina Division of Public Health developing the North Carolina Maternity Center Breastfeeding Friendly Designation (NC MCBFD). This initiative is supported by the North Carolina Hospital Association and other health professional organizations and is designed to assist hospitals in their efforts to begin implementing policies of the Baby-Friendly Hospital Initiative. The NC MCBFD awards one star for every two steps of the Ten Steps to Successful Breastfeeding that a facility has implemented. Further examination of action taken and programs instituted over the past four years is essential to determine the current status of breastfeeding in North Carolina and evaluate what progress the state has made since release of the blueprint for action in 2006.
Study Limitations
There are several limitations of this study. Breastfeeding is measured retrospectively in the CHAMP survey, i.e., mothers are asked to report on child’s history of breastfeeding. Mothers with teenage children may be somewhat less reliable in recalling the specific duration of breastfeeding their adolescent (e.g., three months vs. six months vs. nine months, etc.). We attempted to control for this recall bias, however, by categorizing long duration breastfeeding as the broad grouping of three or more months, thereby reducing the potential for misclassification. Although CHAMP also includes measures on formula feeding, breastfeeding exclusivity is not included in the current report since duration of exclusive breastfeeding was not assessed. Secondly, the child’s height and weight were reported by proxy (maternal report) that can lead to inaccurate values, particularly for child height. To increase accuracy in parental reports of height and weight a callback survey was instituted in 2007 where updated height and/or weight measurements were obtained from parents who guessed or relied on the child’s self-reporting of height and weight. Thirdly, the BRFSS and CHAMP are surveys of households with landline telephones. By not including households without telephone service or cell phone only households it is likely that some populations may be under-represented in the sample (e.g., low income). However, by including mother’s education as proxy for socioeconomic status in the logistic regression model the effect of these factors on study results are controlled for to some extent. Lastly, an observational study such as this can only show an association between breastfeeding and child overweight — it cannot demonstrate cause and effect.
Conclusion
The results of this study suggest that breastfeeding is a protective factor against child overweight among children ages 2 to 17 in North Carolina. The American Academy of Pediatrics recommends that mothers breastfeed exclusively for at least six months, with continued breastfeeding for at least the first year of life, and beyond for as long as mutually desired by mother and child. Previous research offers several strategies that could be undertaken by the public health community to promote breastfeeding in North Carolina: (1) enacting recommendations specified by the CDC in the state report: Maternity Practices in Infant Nutrition and Care in North Carolina;38 (2) increasing the number of breastfeeding peer supporters, or support programs, associated with county health departments; (3) ensuring that all new mothers in North Carolina receive information on the health benefits of breastfeeding for their infants; and (4) research and evaluation of strategies and objectives specified in the North Carolina’s 2006 action plan for promoting breastfeeding.46 Following these recommendations to promote breastfeeding could reduce the burden of childhood obesity in North Carolina.SCHS Study No. 164 ♦ October 2010 8 State Center for Health Statistics
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References
1. Arenz S, Rückerl R, Koletzko B, von Kries R. Breast-feeding and childhood obesity — a systematic review. International Journal of Obesity. 2004;28:1247–56.
2. Owen CG, Martin RM, Whincup PH, Smith GD, Cook DG. Effect of Infant Feeding on the Risk of Obesity Across the Life Course: A Quantitative Review of Published Evidence. Pediatrics. 2005;115:1367–77.
3. Breastfeeding Among U.S. Children Born 1999–2006, Centers for Disease Control National Immunization Survey. www.cdc.gov/breastfeeding/data/NIS_data/2006/socio-demographic_any.htm. Accessed June 25, 2010.
4. Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention. Breastfeeding Report Card — United States, 2009. www.cdc.gov/breastfeeding/pdf/2009BreastfeedingReportCard.pdf.
5. Weiser TM, Lin M, Garikapaty V, Feyerharm RW, Bensyl DM, Zhu BP. Association of maternal Smoking Status With Breastfeeding Practices: Missouri, 2005. Pediatrics. 2009;124:1603–10.
6. Jevitt C, Hernandez I, Groer M. Lactation complicated by overweight and obesity: Supporting the mother and newborn. J Midwifery Women’s Health. 2007;52:606–13.
7. White House Task Force on Childhood Obesity Report to the President: Solving the Problem of Childhood Obesity Within a Generation, May 2010. Let’s Move Web site. www.letsmove.gov/pdf/TaskForce_on_Childhood_Obesity_May2010_FullReport.pdf. Accessed May 12, 2010.
8. The White House: Office of the Press Secretary. “Childhood Obesity Task Force Unveils Action Plan: Solving the Problem of Childhood Obesity Within a Generation,” May 11, 2010. White House Web site. www.whitehouse.gov/search/site/Solving%20the%20problem. Accessed May 12, 2010.
9. Miles DR, Herrick H, Ford CA. The North Carolina Child Health Assessment and Monitoring Program: Survey Methodology and Data Collection. Statistical Primer No. 18. Raleigh, NC: State Center for Health Statistics; 2010.
10. Kuczmarski RJ, Ogden CL, Guo SS, Grummer-Strawn LM, Flegal KM, Mei A, Wei R, Curtin LR, Roche AF, Johnson CL. 2000 CDC growth charts for the United States: Methods and development. National Center for Health Statistics. Vital Health Stat. 2002;11(246).
11. World Health Organization. Physical Status: The Use and Interpretation of Anthropometry. WHO technical report series: 854. Geneva, Switzerland: World Health Organization; 1995.
12. Kuczmarski RJ, Flegal KM. Criteria for definition of overweight in transition: background and recommendations for the United States. American Journal of Clinical Nutrition. 2000;72:1074–81.
13. Reilly JJ, Armstrong J, Dorosty AR, Emmett PM, Ness A, Rogers I, Steer C, Sherriff A. Early life risk factors for obesity in childhood: cohort study. [published online May 20 2005]. BMJ. 2005;330(7504):1357; doi:10.1136/bmj.38470.670903.E0.
14. Li C, Goran MI, Kaur H, Nollen N, Ahluwalia JS. Developmental trajectories of overweight during childhood: Role of early life factors. Obesity. 2007;15(3):760–71.
Acknowledgements
The authors would like to thank the following people from the Nutrition Services Branch for their very helpful contributions: Najmul Chowdhury, M.B.B.S., M.P.H., Public Health Epidemiologist; and Bethany Holloway, M.Ed., R.D., L.D.N., I.B.C.L.C., R.L.C., Breastfeeding Peer Counselor Program Coordinator. The authors would also like to thank Paul Buescher, Ph.D., former director of SCHS, for his helpful comments on earlier drafts of the study.State Center for Health Statistics 9 SCHS Study No. 164 ♦ October 2010
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15. Division of Nutrition and Physical Activity: Research to Practice Series No. 4: Does breastfeeding reduce the risk of pediatric overweight? Atlanta: Centers for Disease Control and Prevention, 2007.
16. Fisher JO, Birch LL, Smiciklas-Wright H, Picciano MF. Breast-feeding through the first year predicts maternal control in feeding and subsequent toddler energy intakes. Journal of the American Dietetic Association. 2000;100:641–6.
17. Heinig MJ, Nommsen LA, Peerson JM, Lonnerdal B, Dewey KG. Energy and protein intakes of breast-fed and formula-fed infants during the first year of life and their association with growth velocity: the DARLING Study. American Journal of Clinical Nutrition. 1993;58:152–61.
18. Locke R. Preventing obesity: the breast milk-leptin connection. Acta Paediatrica. 2002;91:891–4.
19. Singhal A, Lanigan J. Breastfeeding, early growth and later obesity. Obesity Review. 2007;8(Supplement 1):51–4.
20. Pregnancy Risk Assessment Monitoring System (PRAMS) Survey Data 2008: State Center for Health Statistics, Raleigh NC. www.schs.state.nc.us/SCHS/data/prams.cfm. Accessed July 20, 2010.
21. Fairbrother N, Stanger-Ross I. Reproductive-aged women’s knowledge and attitudes regarding infant-feeding practices: an experimental evaluation. Journal of Human Lactation. 2010;26(2):157–67.
22. Khoury AJ, Moazzem SW, Jarjoura CM, Carothers C, Hinton A. Breast-feeding initiation in low-income women: Role of attitudes, support, and perceived control. Women’s Health Issues. 2005;15(2):64–72.
23. Alexander A, O’Riordan MA, Furman L. Do Breastfeeding Intentions of Pregnant Inner-City Teens and Adult Women Differ? [published online June 24 2010]. Breastfeeding Medicine. 2010;doi:10.1089/bfm.2009.0083.
24. Mitra AK, Khoury AJ, Hinton AW, Carothers C. Predictors of breastfeeding intention among low-income women. Maternal and Child Health Journal. 2004;8(2):65–70.
25. Mickens AD, Modeste N, Montgomery S, Taylor M. Peer support and breastfeeding intentions among black WIC participants. Journal of Human Lactation. 2009;25(2):157–62.
26. Li R, Fein SB, Chen J, Grummer-Strawn LM. Why mothers stop breastfeeding: Mothers’ self-reported reasons for stopping during the first year. Pediatrics. 2008;122:S69–S76.
27. Otsuka K, Dennis CL, Tatsuoka H, Jimba M. The relationship between breastfeeding self-efficacy and perceived insufficient milk among Japanese mothers. Journal of Obstetric, Gynecologic, & Neonatal Nursing. 2008;37(5):546–55.
28. Ladomenou F, Kafatos A, Galanakis E. Risk factors related to intention to breastfeed, early weaning and suboptimal duration of breastfeeding. Acta Paediatrica: Nurturing the Child. 2007;96(10):1441–4.
29. Oddy WH, Jianghong L, Landsborough L, Kendall GE, Hendersen L, Downie J. The association of maternal overweight and obesity with breastfeeding duration. Journal of Pediatrics. 2006;149:185–91.
30. Rasmussen KM, Kjolhede CL. Prepregnant overweight and obesity diminish the prolactin response to suckling in the first week postpartum. Pediatrics, 2004;113:465–71.
31. Rasmussen KM, Holson JA, Kjolhede CL. Obesity as a risk factor for failure to initiate and sustain lactation. Advances in Experimental Medicine and Biology. 2002;503:217–22.
32. Chuang CH, Chang PJ, Chen YC, Hsieh WS, Hurng BS, Lin SJ, Chen PC. Maternal return to work and breastfeeding: a population-based cohort study. International Journal of Nursing Studies. 2010;47(4):461–74.
33. The United Nations Children’s Fund. Ten Steps to Successful Breastfeeding. www.unicef.org/nutrition/index_24806.html. Accessed July 30, 2010.
34. Baby-Friendly USA, Inc. 94 US Baby-Friendly Hospitals and Birth Centers as of July 2, 2010. www.babyfriendlyusa.org. Accessed July 30, 2010.
35. Rosenberg KD, Stull JD, Adler MR, Kasehagen LJ, Crivelli-Kovach A. Impact of hospital policies on breastfeeding outcomes. Breastfeeding Medicine. 2008;3(2):110–6.
36. Merten S, Dratva J, Ackermann-Liebrich U. Do baby-friendly hospitals influence breastfeeding duration on a national level? Pediatrics. 2005;116(5):e702–8.SCHS Study No. 164 ♦ October 2010 10 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
37. Centers for Disease Control and Prevention, National Survey of Maternity Practices in Infant Nutrition and Care, 2007. www.cdc.gov/breastfeeding/data/mpinc/index.htm. Accessed July 30, 2010.
38. Maternity Practices in Infant Nutrition and Care in North Carolina, Centers for Disease Control and Prevention, April 2010. www.cdc.gov/breastfeeding/pdf/mPINC/North_Carolina.pdf. Accessed July 30, 2010.
39. Kogan MD, Singh GK, Dee DL, Belanoff C, Grummer-Strawn LM. Multivariate analysis of state variation in breastfeeding rates in the United States, American Journal of Public Health. 2008;98:1872–80.
40. National Conference of State Legislatures, Issues & Research, Breastfeeding laws. www.ncsl.org/default.aspx?tabid=14389. Accessed July 30, 2010.
41. The Patient Protection and Affordable Care Act. P.L. 111–148: Section. 4207. Reasonable Break Time for Nursing Mothers. http://acscan.org/pdf/healthcare/implementation/PPACA-HPA-summary.pdf. Accessed July 30, 2010.
42. State Personnel Manual: Workplace Environment, Health, Wellness and Work/Life — Lactation Support. Section 8, pg 53. www.osp.state.nc.us/manuals/manual99/Lactation%20Support.pdf. Accessed September 8, 2010.
43. North Carolina Licensing Standards and Definitions for Child Care Centers, Rule .0901. http://ncchildcare.dhhs.state.nc.us/pdf_forms/rule_changes_july_aug_2010.pdf. Accessed September 8, 2010.
44. Gross SM, Resnik AK, Cross-Barnet C, Nanda JP, Augustyn M, Paige DM. The differential impact of WIC peer counseling programs on breastfeeding initiation across the state of Maryland. Journal of Human Lactation. 2009;25(4):435–43.
45. Wade D, Haining S, Day A. Breastfeeding peer support: are there additional benefits? Community Practitioner. 2009;82(12):30–3.
46. Mason G, Roholt S. Promoting, Protecting and Supporting Breastfeeding: A North Carolina Blueprint for Action. North Carolina Division of Public Health, Raleigh, NC; 2006.State of North Carolina
Beverly Eaves Perdue, Governor
Department of Health and Human Services
Lanier M. Cansler, Secretary
www.ncdhhs.gov
Division of Public Health
Jeffrey P. Engel, M.D., State Health Director
www.ncpublichealth.com
Chronic Disease and Injury Section
Ruth Petersen, M.D., M.P.H., Chief
State Center for Health Statistics
Karen L. Knight, M.S., Director
www.schs.state.nc.us/SCHS
The North Carolina Department of Health and Human Services does not discriminate on the basis of race, color,
national origin, sex, religion, age, or disability in employment or the provision of services. 10/10
Department of Health and Human Services
State Center for Health Statistics
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No. 164 October 2010
Does Breastfeeding Reduce the Risk of
Child Overweight in North Carolina?
by
Harry Herrick, M.S.P.H., M.S.W., M.Ed.
Donna R. Miles, Ph.D.
Catherine Sullivan, M.P.H., R.D., L.D.N., I.B.C.L.C., R.L.C.
Abstract
Objectives: Numerous studies have found an association between breastfeeding and the risk of child overweight. Our
objective is to examine the relationship between breastfeeding initiation and duration with child overweight among
children and adolescents in North Carolina, while controlling for maternal characteristics.
Methods: From 2007–2009, 3,424 biological mothers completed both the North Carolina Behavior Risk Factor
Surveillance System (BRFSS) and the Child Health Assessment and Monitoring Program (CHAMP) surveys. These
population-based data were used to analyze child overweight (ages 2 to 17 years) among children who were never
breastfed or weaned at an early age (breastfed less than three months), as compared to children who were breastfed for at
least three months.
Results: Multivariate analysis found that breastfeeding duration is significantly associated with child overweight/obesity,
even after controlling for maternal characteristics including race, education, smoking status, and weight status. Children
who were never breastfed were significantly more likely to be overweight/obese (aOR=1.39 [95% CI 1.08, 1.80]), as well
as children who were breastfed for less than three months (aOR=1.33 [95% CI 1.03, 1.71]), compared to children who
were breastfed for three or more months.
Conclusion: Various initiatives aimed at childhood obesity include recommendations promoting breastfeeding. Providing
education and information on breastfeeding, supporting programs to encourage breastfeeding, as well as advancing state
breastfeeding legislation may help reduce the rate of child overweight and obesity.
Harry Herrick and Donna R. Miles are with the State Center for Health Statistics, North Carolina Department of Health and Human Services.
Catherine Sullivan is the State Breastfeeding Coordinator, Nutrition Services Branch, North Carolina Department of Health and Human Services.
SCHS Study No. 164 ♦ October 2010 2 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
Introduction
The benefits of breastfeeding in reducing the risk of childhood overweight have been well-documented. Two meta-analyses* conducted by Arenz et al.1 and Owen et al.2 report that breastfeeding has an inverse association with childhood overweight. Arenz and colleagues examined nine studies, consisting of more than 69,000 participants, and concluded that the likelihood of childhood obesity was 22 percent lower for children who were breastfed as infants compared to those never-breastfed (aOR 0.78 [95% CI 0.71–0.85]). Four of the studies in the Arenz et al. review also reported a decreasing prevalence of overweight with increasing duration of breastfeeding, suggesting an inverse dose-response relationship between breastfeeding duration and obesity. Owen and colleagues reviewed 28 studies, consisting of 298,900 subjects, and also found lower adjusted odds of obesity among breastfed children than among formula-fed children. The relationship between breastfeeding and obesity persisted for older children and adolescents indicating that the benefits of breastfeeding were not limited to early childhood.
Low rates of breastfeeding initiation have long been known to be associated with certain maternal characteristics. Results from the Centers for Disease Control and Prevention (CDC) National Immunization Survey3,4 found that, among infants born in 2006, the overall national rate of breastfeeding initiation was 74 percent. However, for this same birth cohort, breastfeeding initiation varied by maternal education and race/ethnicity. Among mothers with a high school education, breastfeeding initiation was 65 percent, compared to 86 percent among mothers with a college degree. Furthermore, the breastfeeding initiation rate among non-Hispanic African-American mothers was the lowest of any race or ethnic group at 56 percent. Also, maternal smoking and maternal obesity have been associated with decreased rates of breastfeeding initiation and duration.5,6
In addition to research demonstrating the benefits of breastfeeding, strategies to encourage breastfeeding have recently gained national attention. On May 11, 2010, First Lady Michelle Obama unveiled the White House Child Obesity Task Force action plan: Solving the Problem of Childhood Obesity Within a Generation.7 In the unveiling of this plan, Mrs. Obama said: “For the first time, the nation will have goals, benchmarks, and measureable outcomes that will help us tackle the childhood obesity epidemic one child, one family, and one community at a time.”8 In this plan, there are several recommendations specific to the promotion of breastfeeding which include eliciting hospitals and health care providers to empower new mothers to breastfeed, improving breastfeeding support among childcare settings, and eliciting local health departments to develop support programs to encourage and sustain breastfeeding for new mothers.
The purpose of the current study is to examine the association between breastfeeding and child overweight status in North Carolina. Using results from the North Carolina Child Health Assessment and Monitoring Program (CHAMP) Survey, we examined whether the likelihood of being overweight was significantly greater among children who were never breastfed or weaned at an early age (breastfed less than three months), as compared to children who were breastfed for at least three months.
Methods
Data
We combined survey data from the 2007, 2008, and 2009 North Carolina Behavioral Risk Factor Surveillance System (BRFSS) and CHAMP surveys to yield a sufficiently large sample for conducting a multivariate analysis of breastfeeding and its association with child and adolescent overweight. The BRFSS is an annual state-wide telephone survey that uses a random-digit-dial computer-assisted telephone interview to assess health characteristics of non-institutionalized adults age 18 years and older. During the BRFSS interview, respondents living in households with children (0 to 17 years) are asked to participate in CHAMP. One child is randomly selected from the household and the adult identified as most knowledgeable about the health of the selected child is called one to two weeks later to complete the CHAMP survey.9
From 2007–2009, 43,889 adults participated in the NC BRFSS. A total of 12,767 (29%) reported a child under age 18 living in the household, of which 8,072 (63%) participated in CHAMP. The current study was limited to surveys where the CHAMP child’s biological mother completed both the BRFSS and CHAMP surveys, and provided information on the child’s height and weight (N=3,424).
* Meta-analyses are studies of previously published studies on a given topic which meet certain research criteria. In a meta-analysis, the study itself is the unit of analysis. For the two studies mentioned above, the authors “pooled” the reported results from each study to yield a summary risk estimate, or pooled odds ratio.State Center for Health Statistics 3 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
Child Weight Status
Child weight status was estimated from maternal report of child’s height and weight (ages 2 to 17 years) from which Body Mass Index (BMI) percentiles for age and sex were calculated. BMI-for-Age percentiles are endorsed as the appropriate assessment of weight status in children and are determined via CDC charting of BMI,10 which is calculated in the same manner for children as it is for adults: weight (in kilograms) divided by height (in meters) squared. In this study, we defined the prevalence of child overweight as having a BMI equal to or exceeding the age-sex-specific 85th percentile, which also includes children defined as obese (greater than 95th percentile). Child overweight was treated as a dichotomous (yes/no) variable. Children with implausible values of height, weight or BMI were excluded from the study, using World Health Organization exclusion criteria.11
Breastfeeding
Breastfeeding initiation and duration were measured in the 2007–2009 CHAMP surveys. For this study, breastfeeding duration was categorized as: (1) never breastfed, (2) breastfed for less than three months
(1 to 90 days), and (3) breastfed for three or more
months (91+ days).
Maternal Characteristics
Demographic and behavioral characteristics of the mother, including education, race, smoking (current smoker vs. non-smoker), and weight status were obtained from the 2007–2009 BRFSS surveys. Three categories of race were analyzed: white, African American, and other. Hispanic mothers accounted for 64 percent of “other race.” Due to small numbers, Hispanics were not treated as separate group in the logistic regression model.
Maternal weight status was based on self-reported height and weight. Categories for maternal weight status based on BMI were defined as: BMI less than 18.5 classified as underweight; BMI 18.5 to 24.9 classified as normal weight; BMI 25.0 to 29.9 classified as overweight; and BMI greater than 29.9 classified as obese.12 For this study, underweight and normal weight mothers were collapsed into a single group, while overweight and obese mothers were treated as separate groups.
Statistical Analysis
CHAMP data are weighted to represent the total child population (0 to 17 years) of North Carolina. SUDAAN 10.0 software survey procedures were used to account for the complex survey design. All descriptive and multivariate analyses incorporated the sample weights and variance estimators derived from the survey design. Multiple logistic regression was used to compute the adjusted odds ratios for overweight children (the dependent variable), accounting for the effects of breastfeeding duration, maternal race, education, smoking, and weight status (explanatory variables). In this model of child overweight, we controlled for maternal characteristics that are associated with breastfeeding.
Results
Sample Characteristics
Demographic and behavioral characteristics of survey respondents are presented in Table 1. Seventy-one percent
Table 1
Sample Characteristics: 2007–2009 NC BRFSS and CHAMP Surveys (N = 3,424)
N
Weighted Percent
Maternal race
African American
458
19.2
Other race
296
10.2
White
2,659
70.6
Maternal education
Less than or equal to H.S.
939
27.9
Some College/Tech school
1,065
30.7
College graduate
1,419
41.4
Maternal smoking status
Current smoker
666
17.8
Non-smoker
2,752
82.2
Maternal weight status
Obese
961
30.6
Overweight
933
28.7
Normal/underweight
1,363
40.7
Child weight status
Underweight
209
6.5
Normal weight
2,049
59.0
Overweight
555
16.8
Obese
611
17.7
Breastfeeding duration
No days
1,092
31.7
Less than 3 months
893
25.3
3 months or more
1,328
43.0SCHS Study No. 164 ♦ October 2010 4 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
of mothers were white, 19 percent African American, and 10 percent other race. Forty-one percent were college graduates, 31 percent had attended some college or technical school, and 28 percent had a high school education or less. Eighteen percent of mothers were current smokers. Based on BMI categories, 41 percent of mothers were underweight/normal weight, while 28 percent were overweight and 31 percent were obese. Based on child BMI-Age percentile categories, 6 percent of children were underweight, 59 percent were normal weight, 17 percent were overweight, and 18 percent were obese; thus 35 percent of children were categorized as either overweight or obese. Overall, 32 percent of children were never breastfed, 25 percent were breastfed for less than three months, and 43 percent were breastfed for three or more months.
Prevalence and Adjusted Odds of Child Overweight
The unadjusted prevalence and adjusted odds ratios of child overweight for each of the five maternal characteristics included in the logistic regression model are presented in Table 2. Multivariate analysis found that breastfeeding duration is significantly associated with child overweight/obesity, even after controlling for maternal race, education, smoking status, and weight status. Children who were never breastfed were significantly more likely to be overweight/obese (aOR=1.39 [95% CI 1.08, 1.80]), as were children who were breastfed for less than three months (aOR=1.33 [95% CI 1.03, 1.71]), compared with children who were breastfed for three or more months.
In addition, the prevalence of child overweight was found to vary significantly by maternal race, education, smoking status, and weight status. Although the prevalence of child overweight was significantly lower among whites, multivariate analysis found that race was not a significant predictor of child overweight when controlling for other covariates. However, it was found that the adjusted odds of child overweight among mothers with the least amount of education was significantly higher compared to children of mothers with a college degree (aOR=1.43 [95% CI 1.09, 1.87]). Both the unadjusted prevalence and adjusted odds of child overweight was significantly greater among mothers who were current smokers, compared to non-smoking mothers. The strongest predictor of child overweight was maternal weight status. Obese mothers were more than two times as likely to have an overweight/obese child compared to normal weight mothers. Similarly, children of overweight mothers were also much more likely to be overweight/obese (aOR=1.33 [95% CI 1.03, 1.71]).
Table 2
Prevalence of Child Overweight/Obesity by Maternal Characteristics, 2007–2009 NC CHAMP (N = 3,383).
Maternal Characteristics
Weighted Percent of Child Overweight/Obese % (95% CI)
aOR1 (95% CI)
Breastfeeding Duration
Never breastfed
42.8 (38.9–46.7)
1.39** (1.08–1.80)
Breastfed < 3 Months
35.8 (31.8–40.0)
1.33* (1.03–1.71)
Breastfed 3 or More Months
27.7 (24.7–30.9)
1.0 (referent)
Race
African American
43.8 (38.4–49.4)
1.28 (0.97–1.69)
Other Race
40.5 (33.5–47.8)
1.40 (0.97–2.03)
White
31.1 (28.8–33.4)
1.0 (referent)
Education
Less than or Equal to H.S.
44.8 (40.6–49.1)
1.43** (1.09–1.87)
Some College/Tech School
35.6 (31.9–39.5)
1.08 (0.85–1.38)
College Graduate
26.6 (23.7–29.6)
1.0 (referent)
Smoking Status
Current Smoker
44.1 (39.3–49.1)
1.41** (1.10–1.82)
Non-smoker
32.4 (30.1–34.7)
1.0 (referent)
Maternal Weight Status
Obese
49.3 (45.2–54.8)
2.49** (1.95–3.17)
Overweight
33.8 (29.9–37.8)
1.39** (1.08–1.79)
Underweight/Normal Weight
23.9 (21.1–26.9)
1.0 (referent)
* p < .05;
** p < .01
1 aOR = Adjusted Odds Ratio; adjusted for breastfeeding duration, maternal race, education, smoking status, and weight status.State Center for Health Statistics 5 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
Discussion
Key Findings
The results of this study support the extensive body of research that has demonstrated the protective effect of breastfeeding on childhood obesity.1,2 Most notably, we found that, in comparison to children who were breastfed for three or more months, the likelihood of child overweight increased by 39 percent for children who were never breastfed, and by 33 percent for children breastfed for less than three months. This relationship was statistically significant when controlling for factors associated with low rates of breastfeeding initiation, specifically maternal race, education, smoking status, and weight status.
Among the model explanatory factors, the strongest relationship was found between maternal weight status and child weight status. Children of obese mothers were more than twice as likely to be classified as overweight or obese, as compared to children of normal weight mothers. Indeed, much of the research on maternal obesity has found that mothers who are overweight or obese entering pregnancy are likely to have infants with higher birth weight, and, in turn, these infants are also at increased risk for obesity later in life. Longitudinal birth cohort studies have shown that maternal pre-pregnancy obesity was a significant predictor of overweight among older children and adolescents.13,14 Findings from the current study of children ages 2 to 17 underscores the influence of maternal weight status on child weight status from early childhood through late adolescence. Nevertheless, breastfeeding duration remained an independent predictor of child overweight, even when controlling for the strong relationship between maternal and child weight status.
Biological Mechanisms of Breastfeeding
Several theories have been proposed to explain why breastfeeding protects against obesity.15 One theory suggests that breastfed babies work for their food by feeding at the breast; consequently, their satiety center is intact and active. Infants are thus able to self regulate their intake of breast milk by sensing when they are hungry and when they are full, rather than relying on external cues (e.g., bottle feeding).16 Other theories focus on the biochemical role of two hormones, insulin and leptin. Excessive amounts of insulin may lead to increased deposition of fat tissue, while leptin is thought to promote satiation. Breast milk has lower concentrations of insulin than formula, and formula fed infants have been shown to have higher plasma insulin concentration, likely due to higher protein intake.17 Conversely, leptin levels in breastfed babies have been found to be higher than in their formula fed counterparts.18 Lower levels of insulin and higher levels of leptin in breast milk could influence the set points of appetite or metabolism, potentially leading to longer term effects in reducing risk of child overweight.19 Further research in these emerging areas of interest is warranted.
Barriers to Breastfeeding
A mother’s decision to breastfeed can be met with barriers that affect both the desire to breastfeed and the sustainability of breastfeeding. Results from the 2008 North Carolina Pregnancy Risk Assessment Monitoring Program (PRAMS)20 found that, among mothers who never breastfed, the most common reasons for not breastfeeding were that the mother did not like breastfeeding (44%), the mother had other children to take care of (24%), or the mother had to return to school or work (23%). Other study results have shown that breastfeeding may be inhibited by underestimating the health benefits of breastfeeding,21,22 by lack of support from the baby’s father,23 and by the mother’s perceived lack of social support, or support from peers.24,25
The reasons for short-duration breastfeeding point to additional challenges for the mother. Lactation issues (baby had trouble sucking) and nutrition issues (breast milk alone did not satisfy baby) are most often cited as the primary reasons for early weaning (less than three months).26 Mother’s perception of milk insufficiency and low sense of breastfeeding self-efficacy can lead to short duration breastfeeding.27 Early weaning is also associated with birth characteristics, including prematurity, admission to a neonatal ward, and Caesarean birth.28 Women who are overweight or obese before pregnancy are also more likely to breastfeed their infants for shorter duration.29 Obesity and the hormones associated with obesity may also play a role in lactation failure.30,31 For many mothers, however, the principal reason for discontinuing breastfeeding is associated with the need to return to work.32
Strategies to Promote Breastfeeding
The Baby-Friendly Hospital Initiative (BFHI) is a well-recognized strategy that seeks to protect and promote breastfeeding worldwide. Launched in 1991, the initiative is an effort by the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO) to ensure that all maternity facilities become centers of breastfeeding support. Through implementing all UNICEF/WHO policies, known as the Ten Steps, hospitals can become certified as “baby-friendly.”33 As of July 2, SCHS Study No. 164 ♦ October 2010 6 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
2010, only 94 hospitals in the U.S. were certified as baby-friendly. Two of these hospitals are in North Carolina: the Mission Memorial Hospital in Asheville, and the Women’s Birth and Wellness Center in Chapel Hill.34
A number of studies both in the U.S. and in other countries have shown a positive impact of the BFHI on breastfeeding initiation and duration. An institutional survey of Oregon’s maternity hospitals (N=57) found that hospitals that had higher compliance with the BFHI Ten Steps were more likely to have higher rates of breastfeeding for their maternity patients at two days and at two weeks postpartum, compared to hospitals with lower compliance. Furthermore, when each of the Ten Steps was analyzed individually, having a written hospital policy in place was found to be the most important step associated with higher breastfeeding rates.35 A study of maternity hospitals (N=145) in Switzerland found that the proportion of exclusively breastfed infants (birth to 5 months) was 42 percent for infants born in baby-friendly hospitals, compared to 34 percent for infants born elsewhere.36 Findings from these types of studies suggest that hospitals with comprehensive breastfeeding policies are increasing the number of new mothers who initiate and sustain breastfeeding.
In 2007, the CDC Maternity Practices in Infant Nutrition and Care (mPINC) national survey assessed perinatal care in maternity hospitals and birth centers in the U.S. that provide maternity care services.37 In North Carolina, 84 percent of the 85 eligible hospitals and birth centers participated in the mPINC survey. The results of the survey revealed that in North Carolina only 9 percent of facilities met the American Academy of Pediatrics Perinatal Care Guidelines against routine supplementation of formula for newborns, only 10 percent had comprehensive breastfeeding policies in place, and only 16 percent do not distribute formula company discharge packs. The mPINC state report for North Carolina outlines recommendations to improve breastfeeding practices and policies specific to the state.38
State legislation, such as protecting a women’s right to breastfeed in public, has also been shown to be an effective strategy for promoting breastfeeding. A recent study conducted by Kogan and colleagues39 found that breastfeeding initiation rates were highest in states (predominantly in the west and northwest) that had enacted multiple pieces of legislation supportive of breastfeeding and lowest among states (predominantly southern) with minimal legislation. Washington state had the highest breastfeeding initiation rate (88%), and North Carolina ranked 31st with an initiation rate of 63.5 percent. Currently, North Carolina has a single piece of legislation stating that a woman is allowed to breastfeed in any public or private location, and that she is not in violation of indecent exposure laws. In California, with the third highest rate of breastfeeding initiation (86.5%), several pieces of legislation have been enacted, including a law that requires the Department of Public Health to develop a training course about hospital policies and recommendations that promote exclusive breastfeeding and specify staff for whom this model training is appropriate.40
Another key strategy for promoting breastfeeding involves educating employers on the health benefits of breastfeeding, and encouraging workplace policies and adaptations, such as private rooms for lactation, that would allow for new mothers to continue feeding their infant breast milk at work. Such policies have now garnered support in the new national health care bill. As part of the Patient Protection and Affordable Care Act signed by President Obama in March 2010, employers are now required to provide reasonable break time for one year for an employee who is subject to the Fair Labor Standards Act (paid hourly), to express breast milk for her nursing child, and provide a private room for this purpose.41 In North Carolina, the Office of State Personnel recently passed a lactation policy that provides space and break time for employees governed by the State Personnel Act,42 protecting salaried employees as well as hourly employees. Additional regulations went into effect on July 1, 2010, stating that all licensed child care facilities and family day care homes must provide accommodations for breastfeeding mothers, including seating and an electrical outlet in a private place other than a bathroom.43 Recently, the North Carolina Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) awarded 57 local agency Breastfeeding Promotion and Support mini-grants in the amount of $417,840 with roughly $106,000 being spent on worksite lactation efforts and $16,000 on training and lending libraries for child care facilities.
Peer support from the community with previous experience in breastfeeding their own children is also known to be effective in promoting breastfeeding. Peer supporters have been shown to be particularly helpful in working with low income populations, such as women in the WIC Program, which have traditionally low rates of breastfeeding initiation. A cross-sectional study of WIC mothers in Maryland (N=18,789) found that peer counseling was positively associated with breastfeeding State Center for Health Statistics 7 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
initiation.44 It has also been found that peer supporters may provide additional benefits to new mothers, such as increased self-esteem, greater confidence, parenting skills, and improved family diet.45 In addition, the use of community peer support programs is one of the recommendations for improving breastfeeding, as outlined in the White House Task Force Report on Solving the Problem of Childhood Obesity Within a Generation.7 The North Carolina WIC Program recently increased their peer counselor programs from 23 to 66 statewide, such that peer counselor programs are now available in all six perinatal regions of the state.
Creating a breastfeeding-friendly health care system, promoting legislation and policies that support breastfeeding, encouraging breastfeeding-friendly workplaces, and developing breastfeeding-friendly communities (e.g., local-based support groups) are some of the key recommendations outlined in North Carolina’s state plan for breastfeeding, entitled “Promoting, Protecting and Supporting Breastfeeding: A North Carolina Blueprint for Action, 2006.”46 Additional recommendations include advocating for insurance coverage for breastfeeding care, involving media to promote breastfeeding public acceptance, and encouraging research and evaluation on breastfeeding outcomes. The action steps defined in the report are also nuanced to the needs of North Carolina, such as the North Carolina Division of Public Health developing the North Carolina Maternity Center Breastfeeding Friendly Designation (NC MCBFD). This initiative is supported by the North Carolina Hospital Association and other health professional organizations and is designed to assist hospitals in their efforts to begin implementing policies of the Baby-Friendly Hospital Initiative. The NC MCBFD awards one star for every two steps of the Ten Steps to Successful Breastfeeding that a facility has implemented. Further examination of action taken and programs instituted over the past four years is essential to determine the current status of breastfeeding in North Carolina and evaluate what progress the state has made since release of the blueprint for action in 2006.
Study Limitations
There are several limitations of this study. Breastfeeding is measured retrospectively in the CHAMP survey, i.e., mothers are asked to report on child’s history of breastfeeding. Mothers with teenage children may be somewhat less reliable in recalling the specific duration of breastfeeding their adolescent (e.g., three months vs. six months vs. nine months, etc.). We attempted to control for this recall bias, however, by categorizing long duration breastfeeding as the broad grouping of three or more months, thereby reducing the potential for misclassification. Although CHAMP also includes measures on formula feeding, breastfeeding exclusivity is not included in the current report since duration of exclusive breastfeeding was not assessed. Secondly, the child’s height and weight were reported by proxy (maternal report) that can lead to inaccurate values, particularly for child height. To increase accuracy in parental reports of height and weight a callback survey was instituted in 2007 where updated height and/or weight measurements were obtained from parents who guessed or relied on the child’s self-reporting of height and weight. Thirdly, the BRFSS and CHAMP are surveys of households with landline telephones. By not including households without telephone service or cell phone only households it is likely that some populations may be under-represented in the sample (e.g., low income). However, by including mother’s education as proxy for socioeconomic status in the logistic regression model the effect of these factors on study results are controlled for to some extent. Lastly, an observational study such as this can only show an association between breastfeeding and child overweight — it cannot demonstrate cause and effect.
Conclusion
The results of this study suggest that breastfeeding is a protective factor against child overweight among children ages 2 to 17 in North Carolina. The American Academy of Pediatrics recommends that mothers breastfeed exclusively for at least six months, with continued breastfeeding for at least the first year of life, and beyond for as long as mutually desired by mother and child. Previous research offers several strategies that could be undertaken by the public health community to promote breastfeeding in North Carolina: (1) enacting recommendations specified by the CDC in the state report: Maternity Practices in Infant Nutrition and Care in North Carolina;38 (2) increasing the number of breastfeeding peer supporters, or support programs, associated with county health departments; (3) ensuring that all new mothers in North Carolina receive information on the health benefits of breastfeeding for their infants; and (4) research and evaluation of strategies and objectives specified in the North Carolina’s 2006 action plan for promoting breastfeeding.46 Following these recommendations to promote breastfeeding could reduce the burden of childhood obesity in North Carolina.SCHS Study No. 164 ♦ October 2010 8 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
References
1. Arenz S, Rückerl R, Koletzko B, von Kries R. Breast-feeding and childhood obesity — a systematic review. International Journal of Obesity. 2004;28:1247–56.
2. Owen CG, Martin RM, Whincup PH, Smith GD, Cook DG. Effect of Infant Feeding on the Risk of Obesity Across the Life Course: A Quantitative Review of Published Evidence. Pediatrics. 2005;115:1367–77.
3. Breastfeeding Among U.S. Children Born 1999–2006, Centers for Disease Control National Immunization Survey. www.cdc.gov/breastfeeding/data/NIS_data/2006/socio-demographic_any.htm. Accessed June 25, 2010.
4. Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention. Breastfeeding Report Card — United States, 2009. www.cdc.gov/breastfeeding/pdf/2009BreastfeedingReportCard.pdf.
5. Weiser TM, Lin M, Garikapaty V, Feyerharm RW, Bensyl DM, Zhu BP. Association of maternal Smoking Status With Breastfeeding Practices: Missouri, 2005. Pediatrics. 2009;124:1603–10.
6. Jevitt C, Hernandez I, Groer M. Lactation complicated by overweight and obesity: Supporting the mother and newborn. J Midwifery Women’s Health. 2007;52:606–13.
7. White House Task Force on Childhood Obesity Report to the President: Solving the Problem of Childhood Obesity Within a Generation, May 2010. Let’s Move Web site. www.letsmove.gov/pdf/TaskForce_on_Childhood_Obesity_May2010_FullReport.pdf. Accessed May 12, 2010.
8. The White House: Office of the Press Secretary. “Childhood Obesity Task Force Unveils Action Plan: Solving the Problem of Childhood Obesity Within a Generation,” May 11, 2010. White House Web site. www.whitehouse.gov/search/site/Solving%20the%20problem. Accessed May 12, 2010.
9. Miles DR, Herrick H, Ford CA. The North Carolina Child Health Assessment and Monitoring Program: Survey Methodology and Data Collection. Statistical Primer No. 18. Raleigh, NC: State Center for Health Statistics; 2010.
10. Kuczmarski RJ, Ogden CL, Guo SS, Grummer-Strawn LM, Flegal KM, Mei A, Wei R, Curtin LR, Roche AF, Johnson CL. 2000 CDC growth charts for the United States: Methods and development. National Center for Health Statistics. Vital Health Stat. 2002;11(246).
11. World Health Organization. Physical Status: The Use and Interpretation of Anthropometry. WHO technical report series: 854. Geneva, Switzerland: World Health Organization; 1995.
12. Kuczmarski RJ, Flegal KM. Criteria for definition of overweight in transition: background and recommendations for the United States. American Journal of Clinical Nutrition. 2000;72:1074–81.
13. Reilly JJ, Armstrong J, Dorosty AR, Emmett PM, Ness A, Rogers I, Steer C, Sherriff A. Early life risk factors for obesity in childhood: cohort study. [published online May 20 2005]. BMJ. 2005;330(7504):1357; doi:10.1136/bmj.38470.670903.E0.
14. Li C, Goran MI, Kaur H, Nollen N, Ahluwalia JS. Developmental trajectories of overweight during childhood: Role of early life factors. Obesity. 2007;15(3):760–71.
Acknowledgements
The authors would like to thank the following people from the Nutrition Services Branch for their very helpful contributions: Najmul Chowdhury, M.B.B.S., M.P.H., Public Health Epidemiologist; and Bethany Holloway, M.Ed., R.D., L.D.N., I.B.C.L.C., R.L.C., Breastfeeding Peer Counselor Program Coordinator. The authors would also like to thank Paul Buescher, Ph.D., former director of SCHS, for his helpful comments on earlier drafts of the study.State Center for Health Statistics 9 SCHS Study No. 164 ♦ October 2010
North Carolina Division of Public Health Breastfeeding and Child Overweight
15. Division of Nutrition and Physical Activity: Research to Practice Series No. 4: Does breastfeeding reduce the risk of pediatric overweight? Atlanta: Centers for Disease Control and Prevention, 2007.
16. Fisher JO, Birch LL, Smiciklas-Wright H, Picciano MF. Breast-feeding through the first year predicts maternal control in feeding and subsequent toddler energy intakes. Journal of the American Dietetic Association. 2000;100:641–6.
17. Heinig MJ, Nommsen LA, Peerson JM, Lonnerdal B, Dewey KG. Energy and protein intakes of breast-fed and formula-fed infants during the first year of life and their association with growth velocity: the DARLING Study. American Journal of Clinical Nutrition. 1993;58:152–61.
18. Locke R. Preventing obesity: the breast milk-leptin connection. Acta Paediatrica. 2002;91:891–4.
19. Singhal A, Lanigan J. Breastfeeding, early growth and later obesity. Obesity Review. 2007;8(Supplement 1):51–4.
20. Pregnancy Risk Assessment Monitoring System (PRAMS) Survey Data 2008: State Center for Health Statistics, Raleigh NC. www.schs.state.nc.us/SCHS/data/prams.cfm. Accessed July 20, 2010.
21. Fairbrother N, Stanger-Ross I. Reproductive-aged women’s knowledge and attitudes regarding infant-feeding practices: an experimental evaluation. Journal of Human Lactation. 2010;26(2):157–67.
22. Khoury AJ, Moazzem SW, Jarjoura CM, Carothers C, Hinton A. Breast-feeding initiation in low-income women: Role of attitudes, support, and perceived control. Women’s Health Issues. 2005;15(2):64–72.
23. Alexander A, O’Riordan MA, Furman L. Do Breastfeeding Intentions of Pregnant Inner-City Teens and Adult Women Differ? [published online June 24 2010]. Breastfeeding Medicine. 2010;doi:10.1089/bfm.2009.0083.
24. Mitra AK, Khoury AJ, Hinton AW, Carothers C. Predictors of breastfeeding intention among low-income women. Maternal and Child Health Journal. 2004;8(2):65–70.
25. Mickens AD, Modeste N, Montgomery S, Taylor M. Peer support and breastfeeding intentions among black WIC participants. Journal of Human Lactation. 2009;25(2):157–62.
26. Li R, Fein SB, Chen J, Grummer-Strawn LM. Why mothers stop breastfeeding: Mothers’ self-reported reasons for stopping during the first year. Pediatrics. 2008;122:S69–S76.
27. Otsuka K, Dennis CL, Tatsuoka H, Jimba M. The relationship between breastfeeding self-efficacy and perceived insufficient milk among Japanese mothers. Journal of Obstetric, Gynecologic, & Neonatal Nursing. 2008;37(5):546–55.
28. Ladomenou F, Kafatos A, Galanakis E. Risk factors related to intention to breastfeed, early weaning and suboptimal duration of breastfeeding. Acta Paediatrica: Nurturing the Child. 2007;96(10):1441–4.
29. Oddy WH, Jianghong L, Landsborough L, Kendall GE, Hendersen L, Downie J. The association of maternal overweight and obesity with breastfeeding duration. Journal of Pediatrics. 2006;149:185–91.
30. Rasmussen KM, Kjolhede CL. Prepregnant overweight and obesity diminish the prolactin response to suckling in the first week postpartum. Pediatrics, 2004;113:465–71.
31. Rasmussen KM, Holson JA, Kjolhede CL. Obesity as a risk factor for failure to initiate and sustain lactation. Advances in Experimental Medicine and Biology. 2002;503:217–22.
32. Chuang CH, Chang PJ, Chen YC, Hsieh WS, Hurng BS, Lin SJ, Chen PC. Maternal return to work and breastfeeding: a population-based cohort study. International Journal of Nursing Studies. 2010;47(4):461–74.
33. The United Nations Children’s Fund. Ten Steps to Successful Breastfeeding. www.unicef.org/nutrition/index_24806.html. Accessed July 30, 2010.
34. Baby-Friendly USA, Inc. 94 US Baby-Friendly Hospitals and Birth Centers as of July 2, 2010. www.babyfriendlyusa.org. Accessed July 30, 2010.
35. Rosenberg KD, Stull JD, Adler MR, Kasehagen LJ, Crivelli-Kovach A. Impact of hospital policies on breastfeeding outcomes. Breastfeeding Medicine. 2008;3(2):110–6.
36. Merten S, Dratva J, Ackermann-Liebrich U. Do baby-friendly hospitals influence breastfeeding duration on a national level? Pediatrics. 2005;116(5):e702–8.SCHS Study No. 164 ♦ October 2010 10 State Center for Health Statistics
Breastfeeding and Child Overweight North Carolina Division of Public Health
37. Centers for Disease Control and Prevention, National Survey of Maternity Practices in Infant Nutrition and Care, 2007. www.cdc.gov/breastfeeding/data/mpinc/index.htm. Accessed July 30, 2010.
38. Maternity Practices in Infant Nutrition and Care in North Carolina, Centers for Disease Control and Prevention, April 2010. www.cdc.gov/breastfeeding/pdf/mPINC/North_Carolina.pdf. Accessed July 30, 2010.
39. Kogan MD, Singh GK, Dee DL, Belanoff C, Grummer-Strawn LM. Multivariate analysis of state variation in breastfeeding rates in the United States, American Journal of Public Health. 2008;98:1872–80.
40. National Conference of State Legislatures, Issues & Research, Breastfeeding laws. www.ncsl.org/default.aspx?tabid=14389. Accessed July 30, 2010.
41. The Patient Protection and Affordable Care Act. P.L. 111–148: Section. 4207. Reasonable Break Time for Nursing Mothers. http://acscan.org/pdf/healthcare/implementation/PPACA-HPA-summary.pdf. Accessed July 30, 2010.
42. State Personnel Manual: Workplace Environment, Health, Wellness and Work/Life — Lactation Support. Section 8, pg 53. www.osp.state.nc.us/manuals/manual99/Lactation%20Support.pdf. Accessed September 8, 2010.
43. North Carolina Licensing Standards and Definitions for Child Care Centers, Rule .0901. http://ncchildcare.dhhs.state.nc.us/pdf_forms/rule_changes_july_aug_2010.pdf. Accessed September 8, 2010.
44. Gross SM, Resnik AK, Cross-Barnet C, Nanda JP, Augustyn M, Paige DM. The differential impact of WIC peer counseling programs on breastfeeding initiation across the state of Maryland. Journal of Human Lactation. 2009;25(4):435–43.
45. Wade D, Haining S, Day A. Breastfeeding peer support: are there additional benefits? Community Practitioner. 2009;82(12):30–3.
46. Mason G, Roholt S. Promoting, Protecting and Supporting Breastfeeding: A North Carolina Blueprint for Action. North Carolina Division of Public Health, Raleigh, NC; 2006.State of North Carolina
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